For conventional masks, there have been proposed various methods of causing peripheral portions of a mask to be held in close contact with skin of a wearer for the purpose of preventing leakage of exhaled air and intrusion of outside air.
For example, Patent Document 1 describes a sanitary mask ear-loop cords attached to both right and left side portions of a mask main body, in which an upper portion of the mask main body is once bent downward to an inner side, and then bent again upward to the inner side, and in which a flexible wire is attached to a leading edge of the upper folded portion so that a central part of the leading edge is expanded to enable immovable support of the mask by causing the mask to be held in close contact from a nose part to cheek parts.
Patent Document 2 describes a mask including a main-body portion for covering the face of a wearer, and ear-loop cords attached to the main-body portion, in which auxiliary pieces each made of an air-permeable material are provided on an inner side of the main-body portion so as to be interposed in gaps between the main-body portion and the face of the wearer.
Patent Document 3 describes a three-dimensional mask including a mask main body formed by bonding a pair of right and left non-woven fabric sheets to each other, and ear-loop portions provided on both side portions of the mask main body, the mask main body being horizontally opened at the time of wearing of the three-dimensional mask so that a bonded portion of the non-woven fabric sheets projects forward, in which at least parts of folded-back pieces, which are folded back at a fold portion toward a rear surface side of the mask main body, are bonded to upper portions of the non-woven fabric sheets of the mask main body, the folded-back pieces being horizontally connected to each other and formed to rise at the fold portion from the rear surface side of the mask main body in association with horizontal opening movement of the mask main body.
Patent Document 4 describes a three-dimensional mask including a mask main body having a front-surface-side member made of an air-permeable material, a rear-surface-side member made of an air-permeable material and a convex member including a top, the convex member being sandwiched between the front-surface-side member and the rear-surface-side member, so as to project to the front surface side, and ear-loop portions provided on both sides of the mask main body so as to be engaged with the ears of a wearer, in which the mask main body includes an absence region formed below a lower end portion of the convex member, which is free from the convex member, and in which an elastic member having stretchability is arranged between the front-surface-side member and the rear-surface-side member in a lower end portion of the mask main body, the elastic member shrinking to form a jaw accommodating portion.
Patent Document 5 describes a gathered mask including three-dimensional gathers over an upper edge as well as right and left parts on a rear surface of a mask main body, and a wire provided above the upper part.
Patent Document 6 describes a mask including a nose-portion covering piece and a jaw-portion covering piece which are arranged in an overlapping state on a rear surface of a mask main body formed of a filter member such as non-woven fabric and each of which is made of the same material as that for the mask main body, in which an upper edge portion of the nose-portion covering piece is attached to an upper end portion of the mask main body through intermediation of a linear heat-fused portion curved downward in a circular-arc shape from a central portion in a width direction of the mask main body to both side-end portions, in which a lower edge portion of the jaw-portion covering piece is attached to a lower end portion of the mask main body through intermediation of another linear heat-fused portion curved upward in a circular-arc shape from the central portion in the width direction of the mask main body to both the side-end portions, in which an free-end portion of each of the nose-portion covering piece and the jaw-portion covering piece is formed to be expandable rearward, with the respective heat-fused portions being used as fulcrums, and in which cord attachment jigs are mounted to both the side-end portions of the mask main body so that ear-loop cords are attached to the cord attachment jigs.
Patent Document 7 describes a three-dimensional mask made of non-woven fabric, including a face covering portion and ear-loop portions, in which a V-shaped notch is provided to at least one of an upper side and a lower side of a center of the face covering portion so that the face covering portion is provided with three-dimensional properties by bonding both oblique lines of the notch, in which the face covering portion is formed of a continuous and single non-woven fabric piece, and in which a collar portion jettying upward is provided at a center on an upper side of the face covering portion.